In testing and mounting semiconductor devices, it is necessary that the leads of the device be correctly positioned and that the ends of leads lie in a common plane. This is particularly true for surface-mount devices. The leads of the semiconductor device may be bent sideways, out, in or down, thereby moving the end of the pin from a plane common with the ends of the other pins. In some instances, one or more pins may have a greater height than the others.
Existing planarity inspection equipment is either not cost-effective or performs the inspection "off-line" as in a quality control operation. The hardware required for off-line inspection is inexpensive, however, the inspection is done manually, lead-by lead, making 100% inspection time-consuming as, well as labor cost prohibitive. Automatic equipment which can be used for on-line inspection is actually stand-alone equipment integrated with the other processing equipment.